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Observations on the breeding of Ochre-breasted Antpitta

(Grallaricula flavirostris) in Ecuador

Observaciones sobre la reproducción de la Gralarita Ocrácea (Grallaricula flavirostris) en

Ecuador

Harold F. Greeney1,2, Alejandro Solano-Ugalde2,3, Mery E. Juiña J.1,2 and Rudy A. Gelis2,4

1Yanayacu Biological Station and Center for Creative Studies c o Foch 721 y Amazonas, Quito, Ecuador. 2Natural History of Ecuador’s Mainland Avifauna, 721 Foch y Amazonas, Quito, Ecuador. 3Fundación Imaymana, Paltapamba 476 San Pedro del Valle Nayón, Quito, Ecuador. 4Pluma Verde Tours, Pasaje Manuel García y 18 de Septiembre N20-28, Quito, Ecuador.

revmmoss@yahoo.com

Abstract

The Ochre-breasted Antpitta (Grallaricula flavirostris) is the most widespread species of its genus, occurring from Central

America south to Bolivia. Its nest and eggs have been described from both extremes of its range but data from the central

portion are lacking. Here we report on five nests found at three localities in Ecuador, representing three separate subspe-

cies. Nests and eggs of all three subspecies appear similar, but more data are needed on this highly polymorphic species.

Key words: Ecuador, Ecuador, egg, nest, parental care, nestling diet, Ochre-breasted Antpitta, Grallaricula flavirostris.

Resumen

La Gralarita Ocrácea (Grallaricula flavirostris) es la especie con la distribución más amplia de su género, desde Centro Améri-

ca hasta Bolivia. Su nido y huevos han sido descritos en ambos extremos de su distribución geográfica, pero faltaban datos

de la porción central. Aquí presentamos datos de cinco nidos encontrados en tres localidades en Ecuador, representando

tres subespecies distintas. Los nidos y huevos de las tres subespecies son aparentemente parecidos, pero necesitamos más

datos sobre esta especie variable.

Palabras clave: Ecuador, huevo, nido, cuidado parental, dieta de pichones, Gralarita ocrácea, Grallaricula flavirostris.

Introduction

The genus Grallaricula contains eight species of

small (10-11.5 cm), elusive, and poorly known

antpittas distributed from Costa Rica to Bolivia

(Krabbe & Schulenberg 2003). Most species have

fairly restricted ranges with the exception of the

highly-variable (Robbins & Ridgely 1990) Ochre-

breasted Antpitta (G. flavirostris), which occurs

throughout the range of the genus, and may in-

clude several species (Ridgely & Tudor 1994,

Ridgely & Greenfield 2001). Ochre-breasted

Antpittas inhabit the undergrowth of humid, mid-

elevation forests (500- 2750 m), generally foraging

alone or in pairs (Fjeldså & Krabbe 1990, Krabbe &

Schulenberg 2003). Due to their elusive nature,

there has been little published on their behavior,

but nests have been described from both ex-

tremes of their range, in Costa Rica (ssp. costari-

censis; Holley et al. 2001) and in Bolivia (ssp. bo-

liviana; Maillard & Vogle 2003). Here we provide

novel observations on the reproduction of three of

the currently recognized eight subspecies of

Ochre-breasted Antpitta (Krabbe & Schulenberg

2003), from both the eastern (ssp. flavirostris) and

western (ssp. mindoensis and zarumae) Andean

Artícu

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Ornitología Colombiana 12: 4-9 2012 4

slopes in Ecuador.

Materials and Methods

We studied two nests of the Ochre-breasted

Antpitta in December 2002 on the slopes of the

Sumaco Volcano (SU), Napo Province, Ecuador, at

an elevation of 1750 m. We also studied two

nests at Reserva Intillacta (RI), elevation 1800 m

(00°03`N, 78°42`W), in the Pichincha Province of

northwestern Ecuador where we found one in

September 2006 and one in March 2007. We lo-

cated a final nest in March 2007 at the Buenaven-

tura Reserve (BV) of the Joctococo Foundation, El

Oro province, southwestern Ecuador at an eleva-

tion of 1015 m (03°38.4” S 79°45.5”W). At the SU

nests we used Hi8 video cameras to monitor activ-

ity at the nests with cameras placed on a tripod 5-

6 m from the nest.

Results

Two nests of Ochre-breasted Antpitta were found

in December 2002 at SU (ssp. flavirostris). The first

was found on 3 December at which time it con-

tained two nestlings. The following day they

weighed 6.5 and 7.0 g, respectively. The nestlings

were bare, dark skinned, paler on the ventral sur-

face, with orange legs. Their bills still bore egg

teeth and were orange with pale yellow to white

gapes and strikingly bright orange mouth linings.

Contour and flight feather pins were just begin-

ning to break the skin’s surface. Six days later the

nestlings were covered in thick rusty down (Fig. 1)

and each weighed 13.5 g. Their legs were pale

pink with an orange cast to the feet. Their bills

were similar to previously, but had developed a

dark grey to black coloration along the middle of

the upper mandible. Primary pin feathers had

broken their sheaths 1-1.5 mm and secondary and

tertiary feathers were broken their sheaths 2-3

mm. At this nest we videotaped activity for 230

min from 13:15 to 17:05 h (EST) on 4 December

and for 172 min from 07:15 to 10:05 h on 10 De-

cember. The weather was sunny on both filming

days and we observed two adults feeding the

nestlings.

On 3 December, upon encountering the first nest,

we observed an adult feed one of the nestlings a

ca. 2 cm-long (snout-vent length) Eleutherodacty-

lus sp. frog. The following day during filming of

the nest adults fed the nestlings 11 times. On two

additional occasions adults arrived at the nest with

prey but did not feed the nestlings. Once the

adult ate a small prey item and once they brought

a 4-5 cm, hairless, green lepidopteran larva which

was too big to feed to the nestlings and was con-

sumed by the adult. On only two occasions the

adults arrived without food and sat down to

brood. Additional food items included two nema-

toceran flies (Diptera) and one adult lepidopteran.

Nestlings produced five fecal sacs, two of which

were eaten by the adults and three of which were

carried from the nest. When arriving at the nest

adults spend an average of 26 ± 46 s standing on

the rim, either feeding or peering about before

leaving the nest or sitting to brood. In general they

stayed on the rim longer, peering about and

twitching in typical Grallaricula fashion when they

were preparing to remain at the nest to brood.

The nestlings were brooded during a total of 11

bouts lasting a mean of 16.1 ± 18.0 min (range =

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Greeney et al.

Figure 1. Mid-aged nestling of Ochre-breasted Antpitta (G. f.

flavirostris), December 2002, Napo Province, Ecuador.

3.4-52.2 min). Nestlings were brooded for 177.4

min (77.2%) of the observation time. While

brooding, the adults occasionally stood up and

peered into the nest (7.6 times/h). On only six oc-

casions did they simply peer down into the nest.

On eight standing bouts they probed sharply into

the nest lining 1-4 times. Twenty standing bouts

included rapid probing of the nest lining as de-

scribed for other antpittas (Greeney et al. 2008),

spending 1.2% of time brooding engaged in this

activity and 1.4% of their time engaged in probing

of some type. In total, while adults were present

at the nest they spent the majority of their time sit-

ting quietly on the nestlings, peering about with

sharp movements of their head. All activities in-

volving movement occupied 4.3% of adults’ time

at the nest.

On 10 December the nestlings were fed a total of

25 times. One nestling was fed 10 times, the other

14 times, and once we were unable to determine

which was fed. Parents brought single food items

to the nest, generally small invertebrates. Of 24

feeds, we were unable to see six prey items. Nine

prey items were 5 mm or less, eight prey items

were between 5 and 10 mm, and only two items

were greater than 10 mm (but less than 20 mm).

During feeding visits adults spent an average (±

SD) of only 26±16 s on the nest and an average of

6.0±5.9 min away from the nest. Only once did an

adult brood the nestlings for 1.3 min. During this

time they stood twice (1 and 6 sec), to probe

rapidly into the nest lining. While at the nest, in-

cluding time spent on the rim feeding, adults

spent 3.6% of their time occupied by non-vigilant

activities.

A second nest was discovered at SU on 5 Decem-

ber at which time it contained two eggs (Fig. 2).

The eggs were sub-elliptical and pale brown with

heavy dark brown blotching, fairly evenly distribut-

ed and overlaying paler lavender spots. They

measured 20.9 by 16.6 mm and 20.7 by 16.6 mm,

respectively. Upon our return on 10 December we

observed both nestlings hatching at 09:00 h (Fig.

3). Although not fully out of their shells, both

nestlings were capable of begging when the nest

was gently bumped. The nestlings were dark-

skinned with orange bills, legs, and cloacas. Their

mouth linings were bright orange and their rictal

flanges were pale creamy-yellow. They were bare

with no sign of feathers developing below the skin.

They weighed 6 g together using a 50 g pesola

spring scale. Their tarsi measured 8.0 and 7.9 mm.

Twenty-four hours later their appearance was

unchanged and they weighed 6.5 g together and

their tarsi measured 8.9 and 8.6 mm. We filmed

this nest on 10 December for 214 min from 09:05

to 12:40 h.

At this nest all food items brought by adults were

less than 5 mm. Adults arrived at the nest 16

times, bringing food on only 9 occasions. Only

one fecal sack was produced and was consumed

immediately by the attending adult. Nestlings

were brooded for 73% of the observation period

in bouts lasting 12.1±8.7 min. While brooding, the

adult stood and peered into the nest on only one

occasion (3 s), rapidly probing the lining twice. In-

cluding periods when adults arrived at the nest

www.ornitologiacolombiana.org/revista.htm 2012 | Número 12 6

Breeding of Grallaricula flavirostris

Figure 2. Nest and complete clutch of Ochre-breasted Antpit-

ta (G. f. flavirostris), December 2002, Napo Province, Ecuador.

and were feeding or standing on the rim, move-

ment bouts at the nest occupied 2.0% of the

adult’s time.

At RI we discovered two nests of ssp. mindoensis.

The first was found while clearing a trail on 2 Sep-

tember 2006, at which time we flushed a bird from

a nest attached to the main trunk (80 cm above

the ground) of a canopy tree within partially dis-

turbed forest. Two eggs rested inside a fairly big

mossy nest (outer diameter 7.5 cm, outer height

13.0 cm, and depth 3.8 cm). Eggs were similar to

those described from SU, however they had a

greenish cast to the ground color. The eggs

measured 20.5 by 16.1 mm and 20.4 by 15.0 mm.

This nest was subsequently abandoned and later

discovered to be in use by Scaled Antpitta

(Grallaria guatimalensis), when at the time the nest

looked as if rebuilt.

The second nest, discovered on 4 March 2007,

was about 8 m distant from the first nest. This nest

was simpler (mostly twigs and little moss), and was

supported by a vine tangle (45 cm above ground,

outer diameter 11.7 cm, outer height 9.0 cm, and

inner cup depth 3.8 cm). The nest contained a sin-

gle egg (21.0 by 16.9 mm), similar in pattern and

coloration to those previously described, but with

a greater amount of blotching towards the larger

end. This nest was checked again one week later,

at which time it was found destroyed, with pieces

of eggshell nearby.

We found a fifth nest on 6 March 2007 at BV (ssp.

zarumae). The nest was beside a small stream and

contained a single ca. week-old nestling. The nest

was composed externally of moss and was lined

with dark flexible fibers. Below this mossy struc-

ture was a sparse platform of small sticks and large

leaf petioles. It was placed 1.2 m up in a small

Melastomataceae shrub and supported by three

ca. 3 cm diameter branches (Fig. 4). Externally the

nest was 15.5 cm tall and 11 cm in diameter (1.7

cm deep) appearing to have possibly been built

on top of another nest which accounted for ap-

proximately 6 cm of this total external height. Fig-

ure 5 shows the tall mossy nest and what appears

to be two separate nests piled one upon the oth-

er, separated by a sparse platform of sticks similar

to that described at the bottom of the overall

structure. Internally the nest cup was 7.4 cm wide

and 4.7 cm deep. The single nesting was covered

in dense red-brown down and its primary feathers

were just beginning to break their sheaths (Fig. 4).

www.ornitologiacolombiana.org/revista.htm 2012 | Número 12 7

Greeney et al.

Figure 3. Hatching at a nest of Ochre-breasted Antpitta (G. f.

flavirostris), December 2002, Napo Province, Ecuador.

Figure 4. Nest with single mid-aged nestling of Ochre-

breasted Antpitta (G. f. zarumae), March 2007, El Oro Provin-

ce, Ecuador.

The bill was mostly orange, duskier on the upper

mandible, the gape was pale yellow-white and the

mouth lining was a strikingly bright orange.

Discussion

The nest, in form and placement, and eggs, in col-

or and markings, of Ochre-breasted Antpitta in

Ecuador closely match those of other Grallaricula

antpittas (Greeney et al. 2008 and references

therein). It is interesting to note, however, that the

eggs of ssp. mindoensis appear to vary slightly in

ground-color from those of other subspecies,

more closely matching that described for Rusty-

breasted Antpitta (Grallaricula ferrugineipectus)

(Schwartz 1957). Nests of Ochre-breasted Antpit-

ta have now been described from three countries

within its extensive range: Costa Rica (ssp. costari-

censis; Holley et al. 2001); Ecuador (ssp. flavirostris,

mindoensis and zarumae; this study); Bolivia (ssp.

boliviana; Maillard & Vogel 2003). While all nests

and eggs are described as being superficially simi-

lar, additional detailed studies are required to con-

firm apparent similarities in these and other parts

of its range. With the nests described here, five of

the eight recognized subspecies (Krabbe & Schu-

lenberg 2003) now have published nest descrip-

tions. As species limits are unclear (Ridgely & Tu-

dor 1994; Krabbe & Schulenberg 2003), further

detailed studies of this species are needed, in par-

ticular of vocalizations (Krabbe & Schulenberg

2003), to properly assess how many species-level

taxa are involved.

Perhaps the most remarkable observation from

the data presented here is the apparent shared

use of a nest by Scaled Antpitta and Ochre-

breasted Antpitta, two species which build quite

different nests (Greeney et al. 2008). While we do

not know which species originally built the nest

described here, our observations suggest that

there may be some intergeneric competition for

nesting sites within the Grallariidae. Given that all

G. flavirostris nests described (Holley et al. 2001,

Maillard & Vogel 2003, this study), have been sup-

ported by several rather small branches, it seems

likely that in the case presented here Ochre-

breasted Antpitta was taking advantage of the

platform provided by an old nest of Scaled Antpit-

ta, as many Grallaria spp. often reuse old nesting

sites (HFG pers. observ.). Further observations on

such interactions are needed, however, before any

strong conclusions may be drawn.

Acknowledgments

This study forms part of a series of publications

developed by the Natural History of Ecuador’s

Mainland Avifauna Group (NHEMA). This study

was funded in part by the following: Matt Kaplan

and John V. Moore through the Population Biolo-

www.ornitologiacolombiana.org/revista.htm 2012 | Número 12 8

Breeding of Grallaricula flavirostris

Figure 5. Nest of Ochre-breasted Antpitta (G. f. zarumae),

March 2007, El Oro Province, Ecuador. Upper line (white)

shows where currently active nest has been built on a base of

small sticks and leaf petioles. Lower line (black) shows where

old nest was built on top of a similar base.

gy Foundation, National Geographic Society grant

#W38-08, Field Guides Inc., and the Maryland Or-

nithological Society. This is publication no. 215 of

the Yanayacu Natural History Research Group and

was encouraged and supported by the PBNHS.

We thank Kristof Zyskowski and an anonymous re-

viewer for suggested improvements.

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Greeney et al.

Recibido: 27 de abril de 2010. Aceptado: 27 de febrero de 2012.